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<head><meta charset="utf-8"><title>revert of PR 77885 in ~~beta~~ stable candidate #83139 · t-compiler · Zulip Chat Archive</title></head>
<h2>Stream: <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/index.html">t-compiler</a></h2>
<h3>Topic: <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/revert.20of.20PR.2077885.20in.20~~beta~~.20stable.20candidate.20.2383139.html">revert of PR 77885 in ~~beta~~ stable candidate #83139</a></h3>

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<a name="231484699"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/revert%20of%20PR%2077885%20in%20%7E%7Ebeta%7E%7E%20stable%20candidate%20%2383139/near/231484699" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/revert.20of.20PR.2077885.20in.20~~beta~~.20stable.20candidate.20.2383139.html#231484699">(Mar 23 2021 at 15:01)</a>:</h4>
<p>hey <span class="user-mention" data-user-id="116122">@simulacrum</span> , I just realized that I forgot to take care of the revert of PR <a href="https://github.com/rust-lang/rust/issues/77885">#77885</a></p>



<a name="231484960"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/revert%20of%20PR%2077885%20in%20%7E%7Ebeta%7E%7E%20stable%20candidate%20%2383139/near/231484960" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/revert.20of.20PR.2077885.20in.20~~beta~~.20stable.20candidate.20.2383139.html#231484960">(Mar 23 2021 at 15:02)</a>:</h4>
<p>hm</p>



<a name="231485088"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/revert%20of%20PR%2077885%20in%20%7E%7Ebeta%7E%7E%20stable%20candidate%20%2383139/near/231485088" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/revert.20of.20PR.2077885.20in.20~~beta~~.20stable.20candidate.20.2383139.html#231485088">(Mar 23 2021 at 15:03)</a>:</h4>
<p>we can rebuild stable artifacts today, we'll want a revert PR directly targeting the stable branch to start off</p>



<a name="231487752"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/revert%20of%20PR%2077885%20in%20%7E%7Ebeta%7E%7E%20stable%20candidate%20%2383139/near/231487752" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/revert.20of.20PR.2077885.20in.20~~beta~~.20stable.20candidate.20.2383139.html#231487752">(Mar 23 2021 at 15:16)</a>:</h4>
<p>okay. I see now that <span class="user-mention" data-user-id="123586">@nagisa</span> ’s PR <a href="https://github.com/rust-lang/rust/issues/80838">#80838</a> changed things a bit to give each target the abilty to choose a strategy here, including in an LLVM-version dependant manner. I’m going to “revert” by making the target files always choose the old probe strategy.</p>



<a name="231489779"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/revert%20of%20PR%2077885%20in%20%7E%7Ebeta%7E%7E%20stable%20candidate%20%2383139/near/231489779" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nagisa <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/revert.20of.20PR.2077885.20in.20~~beta~~.20stable.20candidate.20.2383139.html#231489779">(Mar 23 2021 at 15:28)</a>:</h4>
<p>That's probably the most appropriate approach if we're reverting, yes. That said, I'm still conflicted about reverting this at all. Yes, the uwtables aren't quite right, but the unwinding mechanisms are expected to handle that gracefully anyway, I feel.</p>



<a name="231489918"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/revert%20of%20PR%2077885%20in%20%7E%7Ebeta%7E%7E%20stable%20candidate%20%2383139/near/231489918" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/revert.20of.20PR.2077885.20in.20~~beta~~.20stable.20candidate.20.2383139.html#231489918">(Mar 23 2021 at 15:29)</a>:</h4>
<p>Yeah, I'm also not certain, but afaik the bug it fixes is mostly performance and in rareish cases</p>



<a name="231490108"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/revert%20of%20PR%2077885%20in%20%7E%7Ebeta%7E%7E%20stable%20candidate%20%2383139/near/231490108" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nagisa <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/revert.20of.20PR.2077885.20in.20~~beta~~.20stable.20candidate.20.2383139.html#231490108">(Mar 23 2021 at 15:30)</a>:</h4>
<p>We also don't yet enable inline probes on powerpc I guess, so that's not something we need to worry about regressing either.</p>



<a name="231490525"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/revert%20of%20PR%2077885%20in%20%7E%7Ebeta%7E%7E%20stable%20candidate%20%2383139/near/231490525" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/revert.20of.20PR.2077885.20in.20~~beta~~.20stable.20candidate.20.2383139.html#231490525">(Mar 23 2021 at 15:32)</a>:</h4>
<p>okay, PR <a href="https://github.com/rust-lang/rust/issues/83412">#83412</a> is up</p>



<a name="231490791"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/revert%20of%20PR%2077885%20in%20%7E%7Ebeta%7E%7E%20stable%20candidate%20%2383139/near/231490791" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/revert.20of.20PR.2077885.20in.20~~beta~~.20stable.20candidate.20.2383139.html#231490791">(Mar 23 2021 at 15:34)</a>:</h4>
<p>who is better for reviewing it, <span class="user-mention" data-user-id="123586">@nagisa</span> , or <span class="user-mention" data-user-id="116122">@simulacrum</span> ?</p>



<a name="231490824"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/revert%20of%20PR%2077885%20in%20%7E%7Ebeta%7E%7E%20stable%20candidate%20%2383139/near/231490824" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/revert.20of.20PR.2077885.20in.20~~beta~~.20stable.20candidate.20.2383139.html#231490824">(Mar 23 2021 at 15:34)</a>:</h4>
<p><span class="user-mention" data-user-id="123586">@nagisa</span> if possible, I can give it a try if not though</p>



<a name="231490912"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/revert%20of%20PR%2077885%20in%20%7E%7Ebeta%7E%7E%20stable%20candidate%20%2383139/near/231490912" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/revert.20of.20PR.2077885.20in.20~~beta~~.20stable.20candidate.20.2383139.html#231490912">(Mar 23 2021 at 15:35)</a>:</h4>
<p>do you have time to skim over it <span class="user-mention" data-user-id="123586">@nagisa</span> ? It was pretty mechanical. I’m doing a <code>x.py dist </code> build now</p>



<a name="231492203"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/revert%20of%20PR%2077885%20in%20%7E%7Ebeta%7E%7E%20stable%20candidate%20%2383139/near/231492203" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/revert.20of.20PR.2077885.20in.20~~beta~~.20stable.20candidate.20.2383139.html#231492203">(Mar 23 2021 at 15:42)</a>:</h4>
<p>good catches <span class="user-mention" data-user-id="123586">@nagisa</span> . Okay, I think <span class="user-mention" data-user-id="116122">@simulacrum</span> we are probably good to go. I’ll let you know when my local <code>x.py dist</code> finishes.</p>



<a name="231493046"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/revert%20of%20PR%2077885%20in%20%7E%7Ebeta%7E%7E%20stable%20candidate%20%2383139/near/231493046" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/revert.20of.20PR.2077885.20in.20~~beta~~.20stable.20candidate.20.2383139.html#231493046">(Mar 23 2021 at 15:47)</a>:</h4>
<p><span class="user-mention" data-user-id="116083">@pnkfelix</span> when ready (or even maybe just now makes sense) please r+ with a high priority, and maybe bors retry the currently running PR to preempt it</p>



<a name="231498355"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/revert%20of%20PR%2077885%20in%20%7E%7Ebeta%7E%7E%20stable%20candidate%20%2383139/near/231498355" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/revert.20of.20PR.2077885.20in.20~~beta~~.20stable.20candidate.20.2383139.html#231498355">(Mar 23 2021 at 16:16)</a>:</h4>
<p>okay, done</p>



<a name="231498377"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/revert%20of%20PR%2077885%20in%20%7E%7Ebeta%7E%7E%20stable%20candidate%20%2383139/near/231498377" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/revert.20of.20PR.2077885.20in.20~~beta~~.20stable.20candidate.20.2383139.html#231498377">(Mar 23 2021 at 16:16)</a>:</h4>
<p>thanks for that advice <span class="user-mention" data-user-id="116122">@simulacrum</span></p>



<hr><p>Last updated: Aug 07 2021 at 22:04 UTC</p>
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